wow some really hysterical comments on here! in seriousness its pretty interesting to think about the possible positive effects of fermenting in concrete, but I can't think they would ever outweight (sic) the negatives. But I saw an odd thing on pbs last night about how in Jesus' day they used to crush grapes in trenches in the mountainside, and it would run off and ferment in deeper holes in the rock. I guess they were not so pnoid about brett in those days ! and obviously did not have ss, hdpe or the almighty StarSan.
But it got me thinking how interesting to use more modern technology to create cavities in certain types of rock - at certain depths to maintain temp. I don't have any real understanding of engineering or blasting or geology but it would seem pretty doable for some entrepreneuring microbrewery... the type that likes to push boundaries and then market the hell out of that boundary-pushing (DFH?

, but with mineral properties and natural interaction with the earth, and even allowing the stone to dictate fermentation temp - it all sounds pretty interesting in a hippy-dippy non-sanitary kind of way.
Anyone live near Heuco Tanks, Texas? Might be a good place for an open-earth ferm experiment.